Magnetic plug



Jan. 20, 1959 T. E. BROOKS 2,870,384

MAGNETIC PLUG Original Filed Dec. 14, 1945 United States Patent M MAGNETIC PLUG Thomas E. Brooks, Clarinda, Iowa, assignor to Lisle Corporation, Clarinda, Iowa,.a corporation of Iowa Original application December 14, 1945, Serial No. 635,040. Divided and this application September 13, 1952, Serial No. 309,500

1 Claim. (Cl. 317-2015) My present invention relatestomagnetic plugs for gear and other housings wherein plugs are provided with magnets for the purpose of attracting broken gears and other steel or ferrous particles within the housing, this application being a division of my copending application, Serial No. 635,040, filed December 14, 1945, now abandoned.

One object of the invention is to provide a plug which has a practical, yet inexpensive, means for holding the magnet in the plug without the use of bolts, screws, rivets or other retainer elements.

A further object is to provide supporting means for a magnet with relation to a plug so that the magnet may be located within a gear housing or the like without any possibility of the magnet becoming loosened from the plug and thereby entering the housing where it might do damage to gears or the like.

Still a further object is to provide a magnetic plug which will operate to attract articles from circulation in oil or grease used to lubricate gears and other mechanism within the housing.

More specifically, it is an object of the present invention to provide a means for holding a magnet in a plug,

which means consists of displacing certain portions of the plug into coactiug relationship with the crosspiece of the magnet to thereby retain it rigidly positioned in a seat of the plug.

An additional object is to form a specially shaped seat in the plug which snugly receives the bend of a horseshoe type of magnet and has material closely adjacent the sides of the bend so that when this material is displaced, it will effectively overhang the crossbar of the magnet to retain the magnet in rigidly seated position.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my magnetic plug whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claim, and illustrated in the accompanying drawings, wherein:

Figure 1 is a plan view of the plug only of my magnetic plug before the magnet is inserted therein.

Figure 2 is a similar plan view showing the plug complete, that is, with the magnet seated therein and held in the seated position.

Figure 3 is a sectional view on the line 33 of Figure 1 with the magnet in seated position and a portion thereof broken away, the remaining portion being shown in section, but the magnet not yet retained in position.

Figure 4 is a sectional view on the line 44 of Figure 2 showing the magnet in retained position; and

Figure 5 is a sectional view on the line 55 of Figure 4 showing the plug mounted in a transmission housing or the like and showing the ferrous particles attracted thereby, a portion of the magnet being broken away to show the retainer for the magnet.

On the accompanying drawing I have used the reference character P to indicate in general a plug and M a magnet. The plug P has a suitably shaped portion a Patented Jan. 20, 13 5 9 14. The plug is provided with threads 16a,to screw into the boss 12. While I have shown the portion 1011 square,

it may beany other desirable or suitable shape toicoaj'ct vwith anappropriate tool such as a Wrench or the like.

The plug P has a seat 18a therein which is curved as .shown in Figure 5 to snugly fit the bend or cro'sspie'ce 26 of .the magnet.M. At right angles to the section in .FigureS, theplug P is provided with shoulders.28 as shown in Figure 3 .whichare closely adjacent the sides of the magnet and spaced fromeach other substantially the width of the magnet sothat it canbe snugly seated against the seat 18a. The'seat 18a is preferablymade .approximatelysquare in plan view as shown in Figure} to fit the magnet which is likewise approximately square in plan view.

A suitable tool 30, shown dotted in Figure 3 and in solid lines in Figure 6, is engaged with the shoulders 28 and pressed downwardly, the tool being operated in a punch press or the like. As the tool moves downwardly, it displaces portions of the shoulder 28, which portions serve as retainers for the magnet and are indicated at 32 in Figures 2, 4 and 5. This arrangement is particularly adaptable for a plug which is cast of malleable iron, brass or the like.

In Figure 5 I have shown the action of my magnetic plug. Any ferrous particles that might be carried by the oil 16 to a position adjacent the poles of the magnet M are attracted thereto and accumulate thereon as indicated at 18. Periodically the plug may be removed from the housing 14 and the particles removed so that the magnet is ready to attract any further particles that might develop in the operation of the machinery within the housing. The magnetic plug thus makes possible the removal of material which would otherwise cause considerable wear in gears or the like operating within the housing 14.

The shape of the lower end of the tool 30 is substantially the same as the inside of the bend of the magnet except on a smaller radius so that when it displaces the material of the shoulder 28 to form the retainer 32, such material will have the U-shape shown in Figure 5, with suificient thickness to retain the magnet against any possible displacement from the plug which, of course, would be detrimental to the gears or other working parts in the housing 14. The retainers 32 tightly contact the crosspiece 26 of the magnet M and thus the magnet is held assembled with respect to the plug and firmly seated in the seat 18a thereof.

The disclosed magnetic plug provides a simple and inexpensive means to hold the magnet in position and the arrangement disclosed is obviously inexpensive in production and contributes to the supplying of plugs which are comparatively inexpensive. The shoulder 28 being closely adjacent the sides of the magnet eliminates the necessity of the displaced material to form the re tainers 32 having to travel very far in order to properly overhang the crossbar of the magnet and yet have sufficient strength to hold the magnet in position against all possible displacing tendencies.

Some changes may be made in the construction and arrangement of the parts of my magnetic plug without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claim any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

In a magnetic plug, a plug body having an inner end and an outer end, said inner end having a first depressed portion and a second depressed portion within said first depressed portion, so that said second depressed portion shape and size and being of smaller dimension than the dimension of said'first depressed portion so that said second depressed portion is surrounded by said first depressed portion, a U-shaped magnet having a curved bight part and two spaced poles extending from said curved bight part, the outer side of said curved part of the magnet being of substantially the same shape and size as the curved contour of said second depressed portion so that the magnet will fit into said second depressed portion at only a single selected attitude, the depth of said second depressed portion and the thickness of the bight of the U-shaped magnet being selected so 15 2,436,740

that, when the magnet is operatively fitted into said second depressed portion, the inner surface of the bight part of the magnet is spaced below the surface of the first depressed portion, and portions of said first depressed portion, located above said inner surface of the bight part of the magnet, being displaced laterally in two opposite locations to provide magnet retainers which enter between said poles of the U-shaped magnet and overlie and engage the inner surface of the bight part of the magnet, to hold the magnet at a pre-selected attitude securely in the plug body with the poles of the U-shaped magnet extending outwardly relative to said first depressed portion of the plug body.

References Cited in the file of this patent UNITED STATES PATENTS 1,944,208 Bock Jan. 23, 1934 Brooks Feb. 24, 1948 FOREIGN PATENTS 303,076 Great Britain Dec. 27, 1928 566,011 Great Britain Dec. 8, 1944 

